The Anatomy of Six Pack Abs

The abdominals offer more to life than just a sexy, washboard look. While seeing definition in your abs is certainly a sign of leanness, they play a huge role in the simple functions and tasks that we perform numerous times throughout the day.

Understanding the anatomy of the abdominals will lead to a more efficient workout, greater gains in core strength and give you a midsection to be envied.

Rectus Abdominus

This is the section that is known as the six-pack or more accurately the eight-pack. If you’re lean enough, you’ll see them and this is what most of us strive for.

The rectus abdominus is a long sheath like muscle that runs from the pubic bone all the way up to the middle of the rib cage. While it is in fact one muscle, it appears to be sectioned into four parts on either side of the torso. It is simply tendinous creases that create this appearance, allowing for the washboard, or eight pack look.

The two halves on either side are separated by a strong tendinous sheath called the linea alba. This creates even more definition. The appearance of separation becomes greater with further decreases in body fat.

The rectus abdominus is responsible for flexion and lateral flexion of the trunk. Flexing of the spinal column and bringing the pelvis towards the upper torso as well as side to side bending are the primary functions of this muscle. It also aids in stabilizing the trunk when the head is lifted during a supine positioned exercise.

Numerous exercises will strengthen the rectus abdominus but one of the best is the Bicycle exercise. The bicycle exercise involves all of the primary functions of the rectus abdominus including forward and lateral flexion and trunk stabilization as the head is kept off of the ground.

1)     Begin by lying in a supine position with hands clasped loosely behind the head for support.

2)     Lift the head and shoulders off of the ground for the duration of the exercise while bringing the knees in towards the chest.

3)     Alternate bringing the left knee towards the right shoulder and vice versa, in controlled movements.

4)     Continue pedalling in this manner for a prescribed number of reps.

External Oblique

The external oblique runs from the mid rib cage down to the pubic crest on the far sides of the rectus abdominus. The fibres of this muscle run diagonally along the side of the body.

The external obliques are responsible for both flexion and lateral flexion of the trunk, lateral flexion of the spine, rotation of the ribs and pelvis and tilting of the pelvis.

Any unilateral movement or rotational core exercise will work the external obliques well. One of the best is the Side Plank.

1)     Begin by lying on the floor on your side with your head and torso propped up by your elbow.

2)     The elbow should be directly under the shoulder to ensure proper positioning.

3)     While keeping the entire core tight and engaged, lift the hips off the floor so that the body is in a straight line.

4)     Hold this position for as long as possible while maintaining proper form by staying solid and not letting the hips drop.

5)     Repeat on the opposite side.

Internal Oblique

The internal obliques are a smaller, much deeper set of muscles that lie underneath the external obliques. The internal and external obliques run at opposite angles to each other. The external form a V shape, while the internal form an inverted V.

The functions of the internal obliques are much the same as the external. They play a role in flexion, lateral flexion, rotation and compressing the abdomen. The same exercises will strengthen both types of obliques. One effective option is the Diagonal Cable Chop.

1)     Begin by standing at a cable or pulley machine or even with an exercise band hooked on to a stable post above shoulder level.

2)     With arms extended to the side of the body and angled slightly overhead, clasp the handle of the band or cable.

3)     Contract the abs and keep the core tight as you pull the band from one side of the body to the other while simultaneously squatting and lowering the hands, bringing them in to the opposite foot.

4)     Keeping the core tight, return to the starting position and perform a prescribed number of reps.

5)     After completing reps on one side, set up for the opposite side and repeat.


The transverse abdominal muscle lies deep within the abdomen and runs around the body from front to back like a thick belt. It acts something like a corset, responsible for holding all of the organs in place and assisting with things like breathing, coughing and sneezing.

The transverse abdominals are difficult to target through exercise, as they are a muscle that acts as a support to basic bodily functions and not necessarily movement.

The best way to activate the transverse is through an exercise that requires a great amount of stability and balance through the core. Try a rotating T Stab Push Up.

1)     Begin in the standard push up position. Keep the core tight through entire exercise.

2)     After completing the push up, once back in the starting position lift the left arm, keeping it straight and rotate the arm and torso to the left all the way to 90 degrees.

3)     Return to starting position and repeat on the right side. Alternate back and forth between right and left for a prescribed number of reps.

Erector Spinae

The muscles of the erector spinae run along the entire midline of the back. They are deep muscles that are responsible for supporting and protecting the spine, keeping us erect and flexing the spine. These muscles can be felt as bulges that run down the spine on either side.

Although they are often not thought of as part of the abdominal muscles, they are a crucial component in core strength. Without the necessary support that the erector spinae offer, we would not be able to move the trunk or perform any of the basic abdominal exercises.

Weak erector spinae muscles can contribute to back pain and poor posture, which makes strengthening them a crucial aspect of a training program. Try adding Hyper Extensions to your routine.

1)     Begin by lying face down on the floor with arms stretched out straight in front of the head.

2)     Raise the right arm and left leg simultaneously and hold for a few seconds before lowering to starting position. Repeat on the opposite side.

3)     Continue alternating sides for a prescribed number of reps.

Putting it Together

Try adding these simple, yet very effective exercises to your program if you’re looking for a well rounded, complete core workout. You’ll improve core strength, stamina and function while sculpting and toning that much desired six pack.

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